1. Field of the Invention
The present invention relates to a planar phased array antenna, more specifically to a planar phased array antenna that has spatial diversity, polarization diversity, radiation diversity, frequency diversity, etc. to minimize interference for wireless signals in open space.
2. Description of Related Art
An “antenna” for a wireless communication system is an important and necessary element and has to fulfil two requirements. One is the “frequency and bandwidth requirement,” and the other is the “pattern and polarization matching requirement.” Wireless signals in open space are easily susceptible to interference so that the antennas have other features for solving the following problems:
1. Multi-path Phase Cancellation,
2. Wave Depolarization,
3. Pattern Distortion,
4. Frequency Bandwidth,
5. Radiation Hazard,
6. Size, Weight and Shape, and
7. Others.
Most of the forgoing problems affect the quality of wireless signals. The Multi-path Phase Cancellation, Wave Depolarization, Pattern Distortion and Frequency Bandwidth problems can be solved by “Adaptive Antenna Diversity” techniques. That is, the antenna has polarization directions, varieties of electric wave fields, etc., or many antennas are integrated into a single antenna to form a diversity phased-array antenna.
The present invention provides a new planar, phased array antenna with an Adaptive Antenna Diversity technique to fulfil all requirements for a good antenna.